A silver/silver chloride woven electrode with convex based on electrical impedance tomography

Abstract

Advanced wearable medical devices are widely used for health monitoring, i.e. recording and analyzing signals from human organs. However, the signal quality is influenced significantly by medical electrodes, which became the bottleneck for health monitoring due to unstable impedance under long-term daily usage. Here, a novel monitoring electrode was designed with uniform micro-convex shape to increase the impedance reliability of electrode-skin interface in long-term monitoring and under dynamic conditions, and we set up the electrode-skin interface model to describe the electrode-skin interface and impedance distribution clearly. Furthermore, we investigated how the electrodeposition factors affect the electrode deposition uniformity and electrode resistance. In this study, we compared the monitoring performance among two sets of electrodes: 1) Ag electrodes and Ag/AgCl electrodes, 2) plain Ag/AgCl electrodes, jacquard Ag/AgCl electrodes, and commercial wet electrodes. Specifically, the monitoring performance was quantified by the electrode-skin interface impedance during long-term monitoring, under different dynamic conditions. The optimal electrodeposition process was a ‘small step’ multi-potential method with the 1-1.5-2 V mode. The jacquard Ag/AgCl electrodes presented the best monitoring performance under all three measurement scenarios across four types of electrodes. The results indicated that the proposed electrodes could be used for long-term medical monitoring under daily life activities based on electrical impedance tomography.